Final answer:
The United States Supreme Court invalidated the National Recovery Administration in 1935 and the Agricultural Adjustment Administration in 1936, both key agencies of the New Deal, due to concerns over federal government overreach into areas reserved for state authority.
Step-by-step explanation:
The U.S. Supreme Court invalidated two key New Deal agencies during the 1930s, specifically in 1935 and 1936. These were the National Recovery Administration (NRA) and the Agricultural Adjustment Administration (AAA). The NRA was struck down as unconstitutional in the case of A. L. A. Schechter Poultry Corp. v. United States, where the court decided that it improperly delegated legislative power to the executive branch. In 1936, the AAA was also invalidated; the Supreme Court ruled that the federal government did not have the authority to regulate agriculture, as this power was reserved for the states.
President Franklin D. Roosevelt's administration faced substantial criticism from conservatives, particularly due to the Supreme Court's disapproval of federal overreach. In response to these challenges, Roosevelt proposed his "court-packing plan," which aimed to add new justices to the Supreme Court who were favorable towards his New Deal policies. Despite the initial setbacks, the New Deal legacy persisted, as subsequent legislation sought to readdress and maintain some of the original goals of the defunct agencies.